The subject matter disclosed herein generally relates to a permanent magnet rotor and, more particularly, to the interior placement of permanent magnets within a permanent magnet rotor.
Permanent magnet (PM) synchronous motors are found in a broad assortment of applications ranging from automotive, aircraft, watercraft, robotics, machinery, and other areas as well. As way of example only, in aerospace electromechanical drives have been used in electric fuel pumps, electric actuation systems for flight control, electric cabin air compressors, nitrogen generation systems, compartment refrigeration units, and supplemental cooling units.
A number of different arrangements of the magnets have been provided within permanent magnet motors. For example, as shown in FIG. 1A through FIG. 1F rotor configuration for PM synchronous motors have included: (a) surface-magnet rotor; (b) spoke-type magnet rotor; (c) interior-magnet rotor with flat PMs; (d) inset-magnet rotor; (e) rotor with double-layer interior magnets; and (f) rotor with buried magnets asymmetrically distributed. d-axis (direct axis) is the center axis of magnetic pole, q-axis (quadrature axis) is the axis electromagnetically orthogonal to the d-axis. However, this list is not exhaustive of all possible arrangements.
Accordingly, there is a constant desire for improvements in the magnet arrangement within these PM motors to provide desired motor properties.